Heretofore, preparation of a slide used in connection with various lectures has been conducted in such a manner in which a 35-mm camera 101 is fixedly mounted on a stand 102, facing downwardly, wherein an original 105 is illuminated by light sources 103 such as flash lamps or the like supported on the stand 104 with photographing being carried out by releasing a shutter of the camera 101, as is shown in FIG. 6. In that case, operator is required to adjust the height of the camera in dependence on the size of the original 105 for the purpose of proper focussing. Besides, shutter speed and aperture value have to be determined in dependence on the species of the original 105, the type of the light source 103 and brightness thereof.
Such operation however requires skillfulness, and it was difficult to prepare a desirable slide unless operator has knowledge of the photographical technology.
With a view to eliminating the shortcomings of the prior art mentioned above to thereby provide an image forming apparatus capable of forming a clear image through simplified manipulation without requiring skillfulness, the applicant of this application has made a proposal disclosed in Patent Application No. SHO 62-95374.
This apparatus includes an original supporting stage, a light source for illuminating an original disposed on the stage, sensitive film holding means for holding detachably a light sensitive film at an image position, an imaging optical system for guiding light reflected from the original to the light sensitive surface of the abovementioned film, a shutter disposed in the imaging optical system for controlling the exposure of the light sensitive film switch means outputting a start signal for initiating the photographing on the light sensitive film, and an operation controller outputting control signals at least for the abovementioned light source and shutter.
The length of optical path extending from the abovementioned light source to the light sensitive film is previously determined. The operation controller mentioned above is characterized by such arrangement that it outputs sequentially a shutter opening signal for opening the shutter, lighting means for causing the light source to emit light a predetermined number of times and a shutter closing signal for closing the shutter.
However, the technique described above has been attended with a new problem that the image suffers from unevenness in density.
The present invention has been made in view of the background described above and contemplates as an object to eliminate unevenness in the density of the photographed image.